Some hinged covers, due to geometry and kinematics, use a pre-tensioned spring to keep the cover in an open and/or closed position. The pre-tensioned spring is deflected to produce mechanical force throughout the motion of the cover and to maintain the position of the hinged cover. However, the use of a pre-tensioned spring can have a number of disadvantages. During assembly, the spring is pre-tensioned by deflecting the spring. The force in the spring is maintained while the spring is connected to the various components of the device. Before it is secured to the device, the spring can be suddenly released from its pre-tensioned state. This sudden release of the spring can result in damage to surrounding components, catapulting of the spring into the air, and injury to technicians. After the cover is assembled, the pre-tensioned spring can complicate maintenance procedures. The cover may need to be removed for repair, replacement, or to access other components. Removing the cover can involve removing the fasteners holding the tensioned spring. This can result in the sudden and uncontrolled release of the spring energy. Further, the reassembly of the cover involves pre-tensioning the spring, which can be a difficult and dangerous task for the technicians.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.